.TH std::gmtime 3 "2024.06.10" "http://cppreference.com" "C++ Standard Libary"
.SH NAME
std::gmtime \- std::gmtime

.SH Synopsis
   Defined in header <ctime>
   std::tm* gmtime( const std::time_t* time );

   Converts given time since epoch as std::time_t value into calendar time, expressed
   in Coordinated Universal Time (UTC).

.SH Parameters

   time - pointer to a time_t object to convert

.SH Return value

   Pointer to a static internal std::tm object on success, or null pointer otherwise.
   The structure may be shared between std::gmtime, std::localtime, and std::ctime and
   may be overwritten on each invocation.

.SH Notes

   This function may not be thread-safe.

   POSIX requires that this function sets errno to EOVERFLOW if it fails because the
   argument is too large.

.SH Example


// Run this code

 #include <ctime>
 #include <iomanip>
 #include <iostream>
 #include <sstream>

 int main()
 {
     setenv("TZ", "/usr/share/zoneinfo/Europe/London", 1); // POSIX-specific

     std::tm tm{}; // get_time does not set all fields hence {}
     tm.tm_year = 2020 - 1900; // 2020
     tm.tm_mon = 7 - 1; // July
     tm.tm_mday = 15; // 15th
     tm.tm_hour = 10;
     tm.tm_min = 15;
     tm.tm_isdst = 1; // Daylight saving in London
     std::time_t t = std::mktime(&tm);

     std::cout << "UTC:   " << std::put_time(std::gmtime(&t), "%c %Z") << '\\n';
     std::cout << "local: " << std::put_time(std::localtime(&t), "%c %Z") << '\\n';
 }

.SH Possible output:

 UTC:   Wed Jul 15 09:15:00 2020 GMT
 local: Wed Jul 15 10:15:00 2020 BST

.SH See also

   localtime converts time since epoch to calendar time expressed as local time
             \fI(function)\fP
   C documentation for
   gmtime
